1. Field of the Invention
Embodiments of the invention are directed to setting up a full-duplex communication session and transitioning between half-duplex and full-duplex during a communication session within a wireless communications system.
2. Description of the Related Art
Communication sessions can conventionally be initiated either as half-duplex sessions (e.g., PTT) or full-duplex sessions (e.g., VoIP). When a synchronous, full-duplex communication is desired between two telecommunication devices, such as a telephone call between two telephones, it is common to have one device attempt to start the communication and bridge the connection by contacting the other device. The telephone system then will either send a signal and/or bridge a full-duplex communication channel on a circuit switch to the other device, and the contacted device will then broadcast an alert, such as a ring or other audible alert, and can also give a visual alert, such as flashing lights or activity on a display, to inform a person near the device that another communication device is attempting to bridge a communication. A person will then answer the contacted device and the full-duplex communication will then be bridged, or if the communication was already bridged, the channel will be maintained.
In existing phone systems, the system overhead to start and then attempt to bridge the full-duplex phone call can be significant. The call-commencing process typically begins with a person signifying that they intend to make a phone call, such as by lifting up a telephone handset or pressing a button for an active line, and then the telephone system accepts the telephone number, determines the intended number, sends the appropriate alerting signal or bridges a communication channel to the other device, and waits for acceptance of the call. This process averages 10 seconds and utilizes system overhead during the entire process. There exists some functionality in the calling devices, such as speed dialing, that can hasten parts of the calling process, but this only partially reduces the calling time.
There is a wireless telecommunication service that provides a quick one-to-one or one-to-many communication half-duplex voice communication that is generically referred to as “Push-To-Talk” (PTT) capability. The specific PTT group of recipient devices for the communicating wireless device is commonly set up by the carrier, and a PTT communication connection is typically initiated by a single button-push on the wireless device that activates a half-duplex communication link between the speaker and each member device of the group, and once the button is released, the device can receive incoming PTT transmissions. In some arrangements, the PTT speaker will have the “floor” where no other group member can speak while the speaker had engaged the PTT button at his or her device. Once the speaker releases the PTT button, any other individual member of the group can engage their PTT button and they will have the floor.
A PTT communication system does not utilize a “ringing” system similar to a standard telephone system, but rather opens up a communication channel to a target wireless device upon a group member being granted the floor to talk, and the floor-holder simply starts to talk with the voice being received at and broadcasted to the target devices. Thus, in a “walkie-talkie” style, the voice from the originating wireless device is simply broadcast from the receiving wireless device, with no “answer” required at the receiving wireless device. As the original voice communication was half-duplex, for a target device to talk back to the originating wireless device (or other group members), the user of the target device presses the PTT button sends a floor-request to attempt to get the floor for the session. Thus, multiple group member devices of a PTT group do not concurrently exchange media in a half-duplex session, as in full-duplex.